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Overview

Dictyosphaeria cavernosa, commonly known as green bubble algae, is a widespread species of green seaweed found in tropical marine environments. It is characterized by its distinct, hollow, bubble-like structure and is often observed growing on rocky substrates in shallow reef areas.

Distribution & habitat

This alga is found globally across the tropical Atlantic, Indian, and Pacific Oceans. It typically inhabits shallow, calm reef flats, tide pools, and rocky crevices. It is frequently found attached to hard substrates such as rocks or dead coral, ranging from the intertidal zone down to subtidal depths.

Appearance

Young specimens of D. cavernosa appear as small, hollow, spherical "bubbles" that are often green to yellow-green in color. As the plant matures, it can grow up to 12 cm in diameter, eventually becoming convoluted, ruptured, or irregularly lobed. Its surface has a honeycomb-like appearance due to the large, visible cells that make up its structure. It is distinguished from the similar-looking D. versluysii by its hollow interior, whereas the latter is solid.

Biology & behavior

This opportunistic species can grow rapidly in environments with high nutrient levels, sometimes forming extensive, thick mats that cover large areas of the reef. The large, hollow chambers of the thallus are efficient at trapping sediments and nutrients, which the alga can then utilize for growth. While it is a native species in many regions, it can exhibit invasive tendencies in reef communities impacted by overfishing or nutrient enrichment, where it may overgrow and smother corals and other benthic organisms.